This study examined the fluid dynamics of a textured blood-contacting surface using a computational fluid-dynamic modeling technique. The texture consisted of a regular array of microfibers of length 50 or 100 μm, spaced 100 μm apart, projecting perpendicularly to the surface. The results showed that the surface texture served as a flow-retarding solid boundary for a laminar viscous flow, resulting in a lowered wall shear stress on the base-plane surface. However, the maximum wall shear stress on the fibers was much higher than the shear stress on the nontextured base plane. At all fractions of fiber height down past 10 μm, the permeability of the textured region greatly exceeded the analytically predictable permeability of an equivalent array of infinite-height fibers. The lowered surface shear stress appears to explain in part the enhanced deposition of formed blood elements on the textured surface.